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African Elephant dying due to Cyanobacteria

  • 22 Sep 2020
  • 5 min read

Why in News

Neuro-toxins in water produced by cyanobacteria killed more than 300 African elephants in the Okavango delta region, Botswana (country in Southern Africa).

  • Neuro-toxins are substances that damage, destroy, or impair the functioning of neural tissue.

Key Points

  • Cyanobacteria:
    • Cyanobacteria, also called blue-green algae, are microscopic organisms found naturally in soils and all types of water.
    • These single-celled organisms (bacteria) live in fresh, brackish (combined salt and freshwater), and marine water.
    • These organisms use sunlight to make their own food.
    • In warm, nutrient-rich (high in phosphorus and nitrogen) environments, cyanobacteria can multiply quickly.
    • Not all produce toxins but scientists say toxic ones are occurring more frequently as climate change drives up global temperatures.
  • Climate Change and Algal Bloom: An algal bloom is a rapid increase in the population of algae or cyanobacteria in an aquatic system.
    • Warming water temperature:
      • Toxic blue-green algae thrive in warm, slow-moving water.
      • Warmer water due to climate change might favor harmful algae.
        • Warmer temperatures prevent water from mixing, allowing algae to grow thicker and faster.
    • Changes in salinity:
      • Climate change might lead to more droughts, which make freshwater saltier. This can cause marine algae to invade freshwater ecosystems.
    • Higher carbon dioxide levels:
      • Algae need carbon dioxide to survive. Higher levels of carbon dioxide in the air and water can lead to rapid growth of algae, especially toxic blue-green algae that can float to the surface of the water.
    • Changes in rainfall:
      • Climate change might affect rainfall patterns, leading to alternating periods of drought and intense storms. This can cause more nutrient runoff into water bodies, feeding more algal blooms.
  • The African elephant:
    • It is the largest animal walking the Earth.
    • Their herds wander through 37 countries in Africa.
    • They are vulnerable as per the International Union for Conservation of Nature (IUCN) Red List.
    • African elephants in Botswana, Namibia, South Africa and Zimbabwe are included in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) Appendix II.
      • Appendix II includes species not necessarily threatened with extinction, but in which trade must be controlled in order to avoid utilization incompatible with their survival.
    • Two Subspecies: The Savanna (or bush) elephant and the Forest elephant.
      • Savanna elephants are larger than forest elephants, and their tusks curve outwards.
      • Forest elephants, a distinct subspecies of African elephants, are uniquely adapted to the forest habitat of the Congo Basin, but are in sharp decline due to poaching for the international ivory trade.
    • The World Elephant Day is celebrated on 12th August every year to spread awareness for the conservation and protection of the largest mammal on land.
      • The day was launched in 2012 to bring attention to the urgent plight of Asian and African elephants.


  • It is a landlocked country of southern Africa.
  • Botswana is mostly flat with a few hills, most of its highest points located along the south-east section of the country (the eastern edge of the Kalahari Basin).
  • The semi-arid Kalahari Desert covers about 70% of Botswana's surface.
    • While Kalahari does receive about 500 millimetres in the wettest parts per annum, the Kalahari is considered a desert because it has a vast surface area covered with sand.
  • Biodiversity: It is home to plants and animals, mostly different types of acacia trees, animals like lion, cheetah, leopard, hyena, antelopes, meerkats, as well as many birds species and reptiles.
  • Indegenous People: It is also home to the tribes like- San people (Bushmen), Tswana, Kgalakgadi, and Herero people.
  • Okavango Delta: It is one of the world's largest inland deltas.
    • It spans about 15,000 square kilometres and is relatively flat topography.

Source: TH

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